People are bad about judging relative risk on lower risk activities, such as whether a 1 in 10,000 chance of death is safer or less safe than a 1 in a million chance of death. But when it comes to simple go/no-go decisions on much riskier activities humans are a bit better at making a sound judgment. Is it a good idea to start a fight with a bear? To engage in a gun fight? To set your house on fire and stay inside it? These sorts of risks people understand and can handle.

Generally speaking, if everyone decided tomorrow that drunk driving, smoking, and obesity were awesome humanity would still endure. Though people wouldn't live quite as long.

Inhale, exhale Consume food *Reproduce occasionally.

most of the stuff kills you after reproductive age, so is pretty much irrelevant to the survival of the species.